Health officials recently announced that an outbreak of measles they believe originated in Disneyland last December has now spread to multiple states, and experts have linked the epidemic to the growing anti-vaccination movement among parents. Here is a timeline of the recent outbreak in California:

February 28, 1998: British physician Andrew Wakefield publishes the first in a long line of 0 scientific studies that link vaccines to autism

June 9, 2004: Mother of three Karen Myers tells new mom Ashley Wheeler about a “great new parenting blog”

April 5, 2011: Group of negligent parents decide to start calling themselves “anti-vaxxers”

September 7, 2011-2014: Anti-vaccination movement spreads to thousands of other parents through direct online contact